Why a "book"? When has a Star Wars movie ever been referred to or thought of as a "book"? I guess "Saga of Boba Fett" doesn't quite roll of the tongue.
I dunno. Personally, nothing that Disney or Marvel puts out excites me, and things like the generic title just reek of "creative decisions by committee" to me. I hope to be proven wrong and learn it's really good, though.